In the MPEG-2 standard, which is an international standard system for moving picture coding, it is possible to describe information regarding color spaces of a moving picture signal (hereinafter, referred to as color space information) in a sequence display extension unit (Non-patent Reference 1). In addition, in the MPEG-4AVC standard, it is possible to describe the color space information in a video usability information unit within a sequence parameter set (Non-patent Reference 2). Here, the color space information represents, for example, colour_primaries (color primaries), transfer_characteristics (photoelectric conversion characteristics), and matrix_coefficients (conversion matrices from RGB into YUV), and for each of these, one type of color space information is selected from among several predetermined types (approximately six to nine types) and described.
On the other hand, for DVD-Video discs, MPEG-2 is adopted as a method for coding video pictures. Here, restrictions are provided for the color space information (Non-patent Reference 3). For example, two types of values are set as default values (in the case where the frame rate is 29.97 Hz) with respect to each of the colour_primaries, transfer_characteristics, and matrix_coefficients that are color space information.
Furthermore, in recent years, the development of displays, whose expressible color spaces are significantly wider than ever (wide color-gamut displays), has been actively undertaken. Responding to this, IEC TC100 has been promoting the standardization of the xvYCC color space as IEC61966-2-4. When comparing the xvYCC color space with conventional color spaces, the expressible color space has been expanded by approximately 100 percent as compared to the sRGB color space, and by approximately 5 percent as compared to the sYCC color space.
As for the conventional DVD-Video discs as described above, it is possible to record, on an identical medium, a moving-picture sequence having color spaces that are different in DVD-Video standards. Furthermore, no restrictions are provided for reproducing the medium on which a mixture of moving picture sequences having such different color spaces are recorded. However, the values set as default values have not been of a practical problem so far since differences between defined color spaces are small.
Non-patent Reference 1: ISO/IEC13818-2: Information technology Generic coding of moving pictures and associated audio information: Video, Second edition, 2000 December.
Non-patent Reference 2: ISO/IEC14496-10: Information technology Coding of audio-visual objects Part10: Advanced video coding, First edition, 2003 December.
Non-patent Reference 3: DVD Specifications for Read-Only Disc, Part 3. Video Specifications Version 1.0, August 1996